CVE-2026-54616 NanaZip: Heap out-of-bounds read in NanaZip SquashFS LZ4 decompressor via unchecked negative return value
An attacker can cause an out-of-bounds read in NanaZip's SquashFS decompressor, potentially leaking heap memory or crashing the application via a crafted archive.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-54616?
CVE-2026-54616 is a high-severity memory corruption vulnerability in M2Team NanaZip, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 1.0.88.0 until stable version 6.0.1698.0 and preview version 6.5.1742.0, the Lz4Decode function in NanaZip.Core/SevenZip/CPP/7zip/Archive/SquashfsHandler.cpp rejects only a zero return from LZ4_decompress_safe even though malformed input produces a negative error value. The negative int is converted to the unsigned SizeT destLen and then truncated into outBufWasWrittenSize, causing ReadBlock to trust an attacker-inflated _cachedUnpackBlockSize. During fragment extraction, an attacker-controlled inode Offset can make memcpy read beyond the _cachedBlock heap allocation and place adjacent heap contents in the extracted file, or crash the process. This issue is fixed in stable version 6.0.1698.0 and preview version 6.5.1742.0.
Weakness: CWE-125
Which versions are affected by CVE-2026-54616?
How do I fix CVE-2026-54616?
No fix has been published for CVE-2026-54616 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-54616 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54616 exists.
Sources
Also known as GHSA-95x5-qvvm-hmfp.